Electronic devices fabricated on semiconductor chips such as processors and logic devices are typically tested before being placed in consumer and commercial electronics devices. Many devices in the current marketplace contain a dozen or more semiconductor chip based devices, all of which should be tested before installation. Based on statistical data, twenty percent or more of the cost of semiconductor chips is related to the cost of testing.
As the world market sales for electronic devices reaches and surpasses hundreds of billions (USD), the costs of testing reaches and surpasses tens of billions. As consumers apply commodity pricing expectations to a growing list of established trusted brand names, the criticality of reliable and cost competitive testing equipment scales with the size of the market.
Before final assembly of an electronics consumer device in which hundreds and even thousands of microelectronics components are needed, each component may need to be tested. If even one single component is defective the device may be rendered useless. Semiconductor chips within such device are commonly made on substrate wafers having diameters of hundreds of millimeters. Thousands or even hundreds of thousands of electrical contact electrodes are typically present, and most or all of these contact electrodes needs to be tested or contacted to apply power and ground signals during the test. By current technology, as further described below, most or all of the contacts are to be touched and tested simultaneously. Given the small size and staggering number of contacts on a given wafer, the demands for precision and reliability placed on testing equipment is high.